The present invention relates to a method for driving a fuel cell vehicle and a fuel cell vehicle.
At present, a fuel cell vehicle has been developed actively. A fuel cell vehicle uses a principle that hydrogen is produced from a fuel by means of a reformer, the obtained hydrogen is supplied to a fuel cell to provide electricity, and a motor is rotated by the obtained electricity. This principle can be applied to not only an automobile running with four wheels but also all types of vehicles such as a motorcycle and a railway train running on rails.
The use of a system which uses a fuel cell to operate a drive unit can provide a vehicle in which the energy efficiency is high, the emission of CO2, which poses a problem of global environment, is less, and NOx is scarcely emitted.
The hydrogen supplied to the fuel cell preferably has higher purity. For example, if Co-containing hydrogen is supplied, the life of the fuel cell decreases significantly. Also, an ingredient other than hydrogen does not contribute to the performance of fuel cell, and the presence of the ingredient introduces the need to make the fuel cell large.
Also, because the fuel cell must be carried on a vehicle and the performance and function of vehicle must be enhanced, the fuel cell is desired to be smaller in size. From this viewpoint, it is necessary to obtain purer hydrogen with high efficiency and to supply it to the fuel cell.
The present invention has been made in view of the above situation, and accordingly an object thereof is to provide a method for driving a fuel cell vehicle and a fuel cell vehicle, in which hydrogen obtained from a fuel can be recovered efficiently with high purity and can be supplied to a fuel cell.
To achieve the above object, the present invention provides a method for driving a fuel cell vehicle, comprising the steps of supplying a fuel to a reformer provided with a hydrogen-permeable separation membrane for selectively allowing hydrogen to pass through to generate hydrogen, supplying the generated hydrogen to a fuel cell, and operating a drive unit by electric power obtained by the fuel cell to run a vehicle.
The reformer provided with a hydrogen-permeable separation membrane can be a membrane reformer.
Also, the hydrogen generated by the reformer can be once stored in a hydrogen absorbing alloy, and the hydrogen can be supplied from the hydrogen absorbing alloy to the fuel cell.
Further, a plurality of hydrogen storage apparatuses incorporating a hydrogen absorbing alloy can be provided so that when some of the hydrogen storage apparatuses absorb hydrogen supplied from the reformer, the other hydrogen storage apparatuses discharge hydrogen and supply it to the fuel cell.
Another aspect of the present invention is a fuel cell vehicle, which comprises a fuel tank; a reformer provided with a hydrogen-permeable separation membrane, for generating hydrogen from a fuel supplied from the fuel tank; a fuel cell supplied with the hydrogen, for obtaining electric power; and a drive unit operated by the electric power.
The reformer provided with a hydrogen-permeable separation membrane can be a membrane reformer.
Also, the reformer provided with a hydrogen-permeable separation membrane can generate hydrogen by CO shift reaction after partial oxidation of the fuel, and hydrogen can be obtained selectively by the hydrogen-permeable separation membrane.
Also, the reformer provided with a hydrogen-permeable separation membrane can generate hydrogen by CO shift reaction after reforming reaction of the fuel carried out by water vapor, and hydrogen can be obtained selectively by the hydrogen-permeable separation membrane.
Further, a hydrogen storage apparatus can be provided which incorporates a hydrogen absorbing alloy for once storing hydrogen from the reformer provided with a hydrogen-permeable separation membrane before the hydrogen is supplied to the fuel cell.
The fuel can be any one or a mixture of two or more of CNG, ethane, propane, butane, gasoline, naphtha, dimetyle ether, and methanol.
As is apparent from the above description, according to the present invention, there are provided a method for driving a fuel cell vehicle and a fuel cell vehicle, in which hydrogen obtained from a fuel can be recovered efficiently with high purity and hydrogen suitable for a fuel cell can be supplied.
Also, when a membrane reformer is used as a reformer, the reaction temperature in reforming fuel can be decreased. Further, the fuel cell automobile in accordance with the present invention can be provided with a hydrogen storage apparatus incorporating a hydrogen absorbing alloy, and the hydrogen outlet of the membrane reformer or a hydrogen-permeable separation membrane can be connected to the hydrogen storage apparatus. Thereby, the partial pressure of hydrogen on the recovery side is decreased, and hydrogen can be withdrawn rapidly from the membrane reformer. Further, since the hydrogen stored in the hydrogen storage apparatus can be used at the time of operation start of automobile, an effect that the running of automobile can be started simultaneously with the operation start can be anticipated. When a plurality of hydrogen storage apparatuses are arranged in parallel, as described above, reduced cost and enhanced equipment performance can further be achieved.
Still further, when compressed natural gas, which is called CNG, propane gas, butane gas, or dimethyl ether is used as a fuel, an infrastructure for supplying these gases has already been built and the tank capacity can be decreased because of high calorific value of these gases.